Caterpillar-tractor.



W. 0.. STARK.

CATERPILLAR TRACTOR.

APPLICATION FILED AUG.20,1913,

Patented Jan; 12, 1915.

2 SHEETS-SHEET 1.

77/ T/TESSES W.O.STARK.

CATERPILLAR TRACTOR.

APPLICATION FILED AUG.20,1913

1,124,351,, Patented Ja11.12,1915.

2 SHEETS-SHEET 2.

wry/E 77 0 'Zza-m 454 7 n si'rans Pawn onion.

WILLIAM O. STARK, OF CHICAGO, ILLINOIS, ASSIGNOR TO BULLOCK TRACTOR COMPANY,

' A CORPORATION OF ILLINOIS.

M CATERPILLAR-TRACTOR.

To all whom it may concern:

Be it known that I, WILLIAM O. STARK, a resident of Chicago, in the county of Cook ahd State of Illinois, a citizen of the United States of America, have invented certain new and useful Improvements inthe Caterpillar Type of Tractors; and I do hereby declare that the following description ofmy said invention, taken in connection with the accompanying sheets of drawings, forms a full, clear, and exact specification, which will enable others skilled in the art to which my said invention appertains to make and use the same.

The object of this resent. invention is the production of an e cient, serviceable and durable tractor of the caterpillar type, one that can be easily handled; that can be operated upon all kinds of roads and in the field, and that can be readily turned within the smallest possible radius.

' Other objects of this invention will hereinafter more fully appear.

This'invention has general reference to the caterpillar type of tractors, and it consists, essentially, in the novel and peculiar combination of parts and details of con-' struction, as hereinafter first fully set forth and described and then pointed. out in. the

claims.

In the drawings already mentioned, which serve to illustrate this invention more fully and form a part of this specification, Figure 1 is a side-elevation of this improved tractor, minor and nonessential details being omitted. Fig. 2 is a transverse sectional elevation on line 11 of Fig. 1. Fig. 3 is a transverse sectional elevation on line 22 of said Fig. 1. Fig. 4 is a plan of the frame structure of this machine.- 7

Like parts are designated by the same characters and symbols of reference in all the figures.

Referringto Fig. 4, the frame structure of this machine comprises two side-members 12, 13, preferably constructed of commercial I-beams, the rear ends of whicharein-wardly deflected to connect to two longitudinal frame-members 14, 15, located parallel to said I-beams 12, 13, and extending rearwardly beyond the same. These two frame- -members 14, 15, are at their rearends connected by two, preferably channel bars'16, 17, and at a suitable distance from the rear end by a cross-channel bar 18, while near the forward endithere is an I-beam 19, and. at

Specification of Letters Patent.

operate caster-wheel fashion, the traction Patented Jan. 12, 1915.

Upon the rearwardl'ylocated channel barsv 16, 17, and 18 there are placed and secured two channel bars 21, 22, in parallel spaced relation upon which channels there is located a bed-plate 71, upon which is mounted an internal combustion motor A of any suitable construction, by which the mechine is operated as will hereinafter more fully appear.

1 In about the middle of the transverse channels 16, 17, and above and below the same there are secured perforated plates 23-24 constructed to receive the pintle or king-bolt 25, of a fifth-wheel, as itwere, 26, from which there are depending three brackets 27, 28 and 29,7the lower ends of which form bearings for an axle 30, upon which are mounted two trailing wheels 31, 32, there being rearwardly projecting from the channel 16 a draw-iron 33 or other suitable contrivance by which the tractor may be coupled to any vehicle that may be connected thereto. These two trailing wheels mechanism being at the forward end of the machine, as will be subsequently described.

At the forward end of the machine there is transversely located a rectangular frame comprising two-side beams 34, .35, and two pairs of end beams 36, 37 This rectangular frame which I shall hereafter term the truck-frame, is supported above the four longitudinal beams 13, 15, 14, 12, by four short I-beams 38, 39, 40, and 41; and 1t 1s constructed to receive the trucks proper, 1nthe following manner. Depending from the end-beams of the truck frame are plates 42, 43, secured underneath the transverse beams by angle-bars 44, 45, said plates being stlifplatesc'arry-bearings 48, 49; and pending from the lon 'tudinal beams 12, 13, there are further bearlngs 50, 51, said bearings being in alinement to receive pivots 52, 53, of two pairs of rocking arms 54, 54, 55, and 55, there being two shafts 56, 57, mountedm I the tubular pivots '52 and 53, upon WhlCh shafts'are secured sprocket-wheels 58, 59,

ar chains 60, 61,which chains may.-

ened to prevent lateral movement by pairs" of braces 46, 47. The lower ends of these which s rocket-wheels are the drivesfortwo caterpill be of any desired construction although I prefer a specially constructed chain which forms the subject matter of a copending application for patent filed by me. llhese chains and their mountings are alike, so that a description of one of these devices will also apply to the other thereof.

At the ends of the rocking arms 55, 55,

Figs. 1 and 2, there are mounted shafts 62,

upon which there are secured sprockettion, I claim as new and desire to secure-by 63, wheels 64, 65, over which the chain 61 is trained. These two end sprockets are smaller in diameter than the driving sprocket 59 so that the chain bears on the ground only directly underneath the driving sprocket 59. By this construction the two points of the chains where they bear upon the ground over which the machine is mov-' ing, form, as it were, pivotal points so that if one caterpillar were to remain stationary and the other were moving, the stationary one would be the pivotal point on which the machine would turn. This construction is of great importance since it enables the machine to be turned in the smallest possible space. llhe rocking arms 5d, 54 and 55,and 55= permit the caterpillars to rise and lower at either end, and to follow the undulations of the ground over which the machine is being moved, with the greatest of ease.

The driving spockets are rotated by mechanism actuated by the motor A in a peculiar manner which said operating mechanism forms the subject matter of an application filed concurrent with the present one,and needs not be here described in. detail except to state that each caterpillar operatesentirely independent of the other, whereby the,

steering and the propelling of the machine is accomplished by varying the speed of the traction means, an increase of speed of the right caterpillar causing the machine to turn to the left, while an increase of speed of the left caterpillar produces the opposite result or, which will be the same, a decrease in speed of one or the other of the caterpillars causes the machine to deviate from its course in the corresponding direction This driving mechanism, briefly described, includes a main motor shaft 66, longitudinally disposed on the main frame, a pair of driving friction disks 67, 67 fastened to said main shaft, a further pair of driven friction disks 68, 68 mounted in suitable bearings at right angles to, and between the driving disks and constructed to engage either of said two driving disks, and gearing 69, 70, connecting the shafts of the driven friction disks to the driving sprocket wheels.

In motors of the internal combustion type, as shown, liquid fuel is required which, if desired, may be contained ina tank B, Fig. 2, superposed by a water reservoir C mounted on one side of the truck-frame, and a radiator D placed at the opposite side of said truck-frame, these tanks and containers being indicated by dotted lines in Figs. 1 and 2.

I have heretofore described with considerable minuteness the construction of this machine, but I desire it understood that many of these details may be changed and parts omitted without departing from the scope of this invention.

Having thus fully described this inven- Letters Patent of the United States:

1. A traction engine including a longitudinally disposed main frame, a motor mounted upon said main frame at its rear end, a pair of swiveling trailing wheels constructed to support the said main frame at its rear end, a transverse frame mounted above said main frame at the forward end thereof, a pair of downwardly extending plates in spaced relation, located at each'end of said transverse frame, a bearing at the lower end of each plate, a shaft in each pair of adjacent plates, a sprocket driving wheel mounted on each shaft between said adjacent plates, a pair of horizontally disposed rocking arms between each pair of adjacent plates, there being tubular trunnions medially of said arms constructed to engage the bearings of said plates, said shafts extending inwardly through andbeyond'the innertubular trunnions, bearings at the ends of said rocking arms, shafts in said bearings, driven sprockets mounted on each of the latter shafts, an endless traction belt trained over each pair of end-sprockets and the medial driving sprocket, and an independently operating pair of driving mechanisms connected to said'motor and each of said endless traction belts, said driving mechanisms being constructed to move said traction belts in forward and backward directions.

in a traction engine, the combination, of a longitudinally disposed -main frame, including side-beams in parallel spaced relation and end and medial beams connecting said side beams, a. pair of trailing wheels at one end of said main frame and supporting the rear end of said machine, a motor mounted upon the main frame at the rear end thereof, a bed-plate mounted upon said main frame medially of its length, a transverse frame at the front end of said main frame mounted upon said mainframe a distance above the upper flanges of said main frame, pairs of side-plates pendlng from the ends of sald transverse frame, hearings in alinement at the ends of each pair of pendant plates, a pair of rocking arms medially pivoted in said bearings, shafts in said rocking arms, there being tubular shaft-ends of said driving sprockets, said driving mechanism being constructed to move said endless traction belt in both a 1.5

forward and backward direction.

In testimony that I claim the foregoing as my invention, 1 have hereunto set my hand in the presence of tWo subscribing Witnesses.

VVELLIAM O. STARK. Witnesses MICHAEL J. STARK, A. N. LURIE. 

